In the southern states spring comes early, and so does mole cricket activity. These pests that primarily live unseen below the soil can be responsible for extensive turfgrass damage if left unchecked.
It is important to monitor lawns for mole cricket activity year-round, but especially during the spring months, to prevent considerable turfgrass damage.
What Do Mole Crickets Look Like?
Mole crickets vary in size depending on the species. Three species occur in Georgia, of which two, the tawny mole cricket and the southern mole cricket, are pest species.
Mole crickets range in color from tan to dark brown and can grow up to 2 inches long. Pest mole crickets have spade-like, digging front legs that resemble the front legs of a mole and live most of their lives in the soil.
Mole Cricket Life Cycle
Mole crickets produce one generation per year, apart from South Florida, where two or more generations may occur per year. Mole crickets spend most of their lives in the soil and prefer sandy soils to harder clay soils.
Adult mole crickets spend their winter months in the soil in a dormant state waiting for more favorable conditions. The adult mole crickets that overwintered in the soil emerge and mate when the soil begins to warm in spring. Females then dig deep in moist soil and lay eggs in tunnels come early spring. Peak egg laying occurs when the soil temperatures reach 75°F. Soil moisture is a good predictor of egg-laying success.
Egg incubation averages three weeks and is shorter in warmer soil temperatures. Mole crickets then develop from eggs to adults through a series of nymph stages. After hatching, young nymphs tunnel extensively as they feed and develop. As nymphs become larger, they become increasingly more destructive and resistant to control.
The mole cricket’s development is not fully complete until the insect matures in the spring of the following year.
Signs of Mole Cricket Activity
In early spring, disturbed soil where adult mole crickets emerge from the ground is an early sign of activity. By the time late summer rolls around and turf damage is visible harm is already done.
You can confirm the presence of mole crickets with a soapy water flush. If your soil is dry, water it well before performing the soapy water flush. Mole crickets tend to stay deeper in dry soil, but moisture brings them closer to the surface.
Soapy Water Flush Technique
The soapy water flush technique is done by mixing 2 tablespoons of liquid dishwashing soap in 1 gallon of water. Then pour the soapy water onto 1 to 2 square feet of the suspected infested area. Any mole crickets present will surface within a few minutes.
Turf Damage Caused by Mole Crickets
Mole crickets cause harm to turfgrass by tunneling and uprooting grasses and feeding on grass roots. Damage can become especially problematic on sand based athletic fields and golf courses where tunneling is easy.
Excessive tunneling can result in an extreme loss of moisture and susceptibility to damage from foot traffic, golf carts, and drought.
Tunneling increases as the season progresses and is more extensive in soils that are sandy or loamy, and less complex in areas with mostly clay soil. While there are no grasses resistant to mole crickets, warm season grasses, such as Bermuda, zoysia, and centipede are more severely damaged. This is due to the fact the mole cricket nymphs become active during these grasses’ peak growing season and damage is often hidden until it is too late.
Mole Cricket Control
Mole cricket control is normally not a one-time application. Successful management requires timely control measures and proper maintenance practices. It is important to maintain proper soil nutrients by testing the soil and applying the recommended fertilizers and lime. It is also important to mow the lawn at the proper height for the grass type and irrigate appropriately.
In lawns and fairways that have a mole cricket infestation, insecticide treatment can be used as a preventative measure to avoid severe damage from animals such as racoons, armadillos, and birds foraging in turf for mole crickets. Often, animals produce more damage to grass than the mole crickets themselves.
When to Treat for Mole Crickets
Typically, there are three times a year when mole cricket damage may warrant treatment:
- Early spring
- Egg hatch
Mole crickets that overwinter become active in early spring. Early spring treatment reduces tunneling damage from adult mole crickets. However, chemical control for adults is not normally recommended during spring unless activity is excessive because once the adult mole crickets lay their eggs, all adults die, and no further damage should occur.
The most important insecticide application for mole crickets is during egg hatch. Depending on weather and location, egg hatch normally occurs between early May through June. Newly hatched nymphs are small and close to the surface. As they grow, they tunnel deeper into the soil and treatments are less effective.
It is easier to treat more vulnerable nymphs in June, July, and even early August, than later treatments of larger mole crickets. However, it is often difficult to convince homeowners to treat during this time because there is little visible evidence of turf damage.
If mole crickets are active in an area during March, April, and May, there will most likely be a treatable population of new-generation nymphs that hatch in that same area in June and July. Once mole cricket damage is visible, it is much more difficult to control.
For successful control, pesticides need to reach mole crickets in their underground tunnels. Insecticides and baits are available for mole cricket control and can be purchased at most garden centers. Such products include granular and sprayable insecticides. When applying any lawn insecticide, it is important to read and follow all label directions carefully.
Being aware of the various pests and diseases that threaten the health of turfgrass is the first step to maintaining a health lawn. You don’t have to do it along. NG Turf is here to help!
If you have questions about turfgrass threats, give our Certified Turfgrass Professionals a call at 770.832.8608 or send an email to info@NGTurf.com.